Do you remember Hypercolor? Back when I was in, oh, junior high or high school, these were all the rage … briefly. Clothes that were thermochromatic — they would change color with heat. So, for example, if you put your hand on the shirt and held it there a few seconds, then your hand print would show on the shirt. Growing up in Florida, we quickly realized that it was pretty silly, because you’d just have these big discolored patches under your arms and wherever you were sweaty. (And a note to parents: why would you ever think it’s a good idea to buy heat-sensitive shorts for adolescent girls?)
I didn’t have one of those fancy full-color shirts, but I did have this one with some disappearing ink: this guy was wearing a dark suit and hat. When the black heated up, it faded away, so his hat disappeared and he was wearing a T-shirt and shorts. Probably long shorts, because those were cool.
Anyway, after the brief life of Hypercolor (which, apparently, American Apparel is trying to revive), I haven’t really seen a lot done with heat-sensitive ink. I dunno, there are some color-changing toys, and mugs with clever things that appear or disappear when you fill them with coffee.
But here, finally, is a really cool use of thermochromatic ink that you can share with your kids: Keep Our Secrets. It’s a board book written and illustrated by Jordan Crane and published by McSweeney’s McMullens, and every page has some heat-sensitive ink on it. This is the sort more like my old T-shirt: it’s black when it’s cold, but vanishes and reveals what’s underneath when it’s heated up.
In the story, a little girl is whispering secrets to a boy, things like “Mr. Hudder’s head is fulla rocks” and “There’s a computer in the trash that knows how to write poetry.” The two kids walk through the house (where it appears the adults are having a pretty raucous party) and the girl continues to point out funny little secrets about the people and things around them. When you heat up the ink, either by rubbing it with your finger or with a hair dryer, the secrets below are revealed. It’s really fun to see what Crane has hidden behind all of the mundane-looking objects and people, and the book is really about looking at the world with a different perspective and a bit of imagination.
Of course, it’s the color-changing ink that really makes the book seem magical. It takes a bit of effort to reveal the images with your fingers and thumb (and they tend to darken back up pretty soon) but a hair dryer is really effective (though loud). The downsides to using the hair dryer are, well, that it’s using a good deal of electricity to read a book and that sometimes you can heat it too much and reveal the next page’s pictures before you’ve read it.
Keep Our Secrets is a blast, not only for the ink gimmick but also because Crane’s illustration style is wonderful. You could read it straight through without vanishing any of the ink and it’s a pretty cute book by itself. All of the hidden images are just the icing on the cake.